Deicer Salt Scaling Resistance Research Articles

Secondary durability implications: Steam cured, carbonated concrete containing limestone filler, and GGBFS

The motivation of this work is three-fold: jurisdictions are moving from general use (GU) cement to general use limestone (GUL) cement or Portland cement (PC) to Portland limestone cement (PLC); ‘carbonation curing regimes’ are being widely considered/studied/implemented; and modular construction using precast elements may achieve ‘lower carbon’ concrete infrastructure. This study aims to examine the interplay between various mix constituents (i.e. GU, GUL, limestone filler (LF), and ground granulated blast furnace slag (GGBFS)), curing regimes (atmospheric (0.04% CO2), accelerated (3% CO2) carbonation, and steam curing), and coupled environmental effects on durability of ready mix and precast concrete. In this study, the term “secondary durability implications” of carbonation processes refers to the effect of carbonation on the concrete's indicators of durability (i.e. water absorption (sorptivity), and rapid chloride permeability) and its durability (i.e. against freeze/thaw cycles and deicer scaling). The results reveal that: 1) a combination of GUL cement +10% GGBFS achieves a lower carbonation depth and a higher compressive strength than the other mix designs in the same curing regime without steam curing; 2) steam curing within 24 h of casting leads to a lower long term strength and a greater carbonation depth for a same mix design that is moist cured; and 3) secondary durability implications of (accelerated and atmospheric) carbonation cured (after 28-day moist curing) concrete for the (GUL cement + 10%GGBFS) prisms exhibit stronger resistance against 300 freeze-thaw cycles and de-icer salt scaling resistance compared to the 301-day moist cured mixes.

Test on Concrete after Adding Foundry Sand

Abstract: Due to ever increasing quantities of waste materials and industrial by-products, solid waste management is the prime concern in the world. Scarcity of land-filling space and because of its ever increasing cost, recycling and utilization of industrial by-products and waste materials has become an attractive proposition to disposal. There are several types of industrial byproducts and waste materials. The utilization of such materials in concrete not only makes it economical, but also helps in reducing disposal concerns. One such industrial by-product is Waste Foundry Sand (SFS). WFS is major byproduct of metal casting industry and successfully used as a land filling material for many years. But use of waste foundry sand (WFS) for land filling is becoming a problem due to rapid increase in disposal cost. In an effort to use the WFS in construction materials, research has being carried out for its possible utilization in making concrete as partial replacement of fine aggregate. In India, approximately 1.71 million tons of waste foundry sand and in Punjab region, approximately 0.17 million tons of waste foundry is produced yearly. This experimental investigation was performed to evaluate the strength and durability properties of M20 (30 MPa) and M30 (40 MPa) grades of concrete mixes, in which natural sand was partial replaced with waste foundry sand (WFS). Natural sand was replaced with five percentage (0%, 5%, 10%, 15%, 20%) of WFS by weight. A total of ten concrete mix proportions M-1, M-2, M- 3, M-4 and M-5 for M20 grade of concrete and M-6, M-7, M-8, M-9 and M-10 for M30 grade of concrete with and without WFS were developed. Compression test, splitting tensile strength test and modulus of elasticity were carried out to evaluate the strength properties of concrete at the age of 7, 28, 91 and 365 days. In non destructive testing, rebound hammer and ultrasonic pulse velocity test were conducted at the age of 28, 91 and 365 days. In case of durability property, abrasion resistance, rapid Chloride Permeability and deicing salt scaling resistance was evaluated at the age of 28, 91 and 365 days. Statistical analysis and comparative study between strength and durability properties of both grade of concrete (M20 and M30) were carried out at the age of 28, 91 and 365 days. XRD study was done to identify the presence of various compounds in M20 grade of concrete with foundry sand in varying percentages replacement of fine aggregate.

Evaluation of the effects of silica fume and air-entrainment on deicer salt scaling resistance of concrete pavements: Microstructural study and modeling

Salt scaling is recognized as one of the most critical durability concerns in concrete structures, specifically for concrete pavements in cold regions. The main objective of this study is to investigate the micro- and macro-scale effects of silica fume and air-entrainment on the mechanical strength and deicer salt scaling resistance of concrete pavements. For this purpose, an extensive set of laboratory tests was performed to determine compressive strength, electrical resistivity, and salt-scaling durability of concrete. The testing matrix comprised eight concrete mixtures including two water-to-binder ratios (0.35, 0.4) with and without silica fume and air entrainment. Further, the microstructure of specimens was investigated using mercury intrusion porosimetry (MIP) and scanning electronic microscopy (SEM). The results indicated that, the concrete containing air-entrainment and silica fume exhibited the best performance in the salt scaling test. The MIP results showed that adding silica fume reduced the volume of total pores and refined the pore size distribution. Moreover, silica fume increased the volume of pores smaller than 10 nm due to proper pozzolanic activity. The tests results were employed in a set of nonlinear regression analyses to establish empirical models to estimate the salt-scaling resistance of air-entrained and non-air-entrained concretes as a function of water to binder, fresh air content, compressive strength, electrical resistivity and characteristics of pore structures in hardened concrete. The presented models can provide a practical yet reliable means to assess the salt scaling resistance in concrete pavements.

Effect of Recycled Rubber Particles on the Deicing Salt-Scaling Durability of Concrete

The present study investigated the effect of reused rubber particles (RRP) on the deicer salt durability of ordinary concrete. Four mixtures were designed, a control concrete (CC) and three other rubber concretes obtained by partial substitution of natural dune sand aggregate with reused rubber particles with 0%, 3%, 6%, and 9% w/w. All studied concretes were subjected to the combined effect of freeze/thaw (56 and 120) cycles with the deicer salt solution of 3% NaCl. The results indicated that RRP improved the deicer-salt scaling resistance of rubber concrete strongly compared with the control. The observed innovative property of RRP could be applied to cement-based materials to improve their deicer salt durability. Further, this environmentally friendly practice could reduce the stock of waste tires and offer a renewable source of construction aggregates.

Factors affecting air-entrainment and performance of roller compacted concrete

The study reported in this paper aims at assessing the key factors affecting the air-entrainment in roller compacted concrete (RCC). The effects of binder content, air-entraining agent (AEA) dosage, workability level, and compaction method on the air-void system and frost resistance of RCC were evaluated. The mixtures were tested to evaluate compressive strength, splitting tensile strength, modulus of elasticity, as well as frost resistance of RCC including freeze–thaw resistance, de-icing salt scaling resistance, and air-void system. The performance of the RCC was compared to that of reference air-entrained and non-air-entrained concrete mixtures. Test results indicated that RCC mixtures with air contents of 5% to 7% and spacing factors lower than 230 μm can be achieved even in relatively dry mixtures with Vebe consistency of 90 s. The air-void network of RCC was found to depend primarily on the consistency level of the concrete and to a lesser extent on the binder content and compaction method. The 28-d compressive strength ranged between 36 and 58 MPa even in the mixtures with a low binder content of 255 kg/m3. Despite the adequate air-void system, the RCC mixtures exhibited low to marginal freeze–thaw resistance. However, the air-entrained RCC mixtures exhibited high durability to deicing salt-scaling with mass loss lower than 400 g/m2 after 50 freeze–thaw cycles.

Effect of initial curing conditions on air permeability and de- icing salt scaling resistance of surface concrete

Enhancing the surface quality of concrete is a key to improve the durability of reinforced concrete. Surface concrete can protect steel bars from corrosion due to the migration of gas, water and ion from the surrounding environment. Therefore, the influence of the initial curing on air permeability and the de-icing salt scaling resistance of surface concrete were investigated in this paper. Firstly, existing bridge structures in the cold region of Japan were surveyed with visual rating and non-destructive test (NDT) for the surface quality of concrete. Secondly, the concrete specimens were prepared for different curing conditions and methods including cold weather concreting, heat or non-heat-supply curing, ex- tending demold period and water-retention sheet. These results showed that concrete curing with sheet or permeability formwork was better than curing in air. Especially, utilizing permeability formwork is greatly effective for the attainment of high surface quality of concrete. Simultaneously, focus on cold weather concreting, could evaluate the appropriate curing period combining with the surface air perme- ability and the de-icing salt scaling resistance of concrete. The surface concrete has better de-icing salt frost resistance, when the surface air permeability coefficient is below 1×10-16m2 or the initial curing period is more than three weeks.

Water absorption of carbonated reactive MgO concrete and its correlation with the pore structure

Water absorption of concrete is an important indicator of concrete durability, which is closely related to the porosity and pore structure of concrete. This study investigates the water absorption behavior of carbonated concrete specimens containing reactive MgO of 10%, 30%, 50%, 70% and 90%. Meanwhile, the corresponding chemical composition and pore structure of each mix was characterized by XRD, TG/DTA, MIP and SEM. Experimental results reveal that the uniform pore structure of carbonated concrete containing 10%, 50%, 70% and 90% reactive MgO result in either high initial sorptivities or high quantities of absorbed water. The gradually microstructural change of a denser outer layer and less-dense inner layer from the surface to the center of the 50% reactive MgO concrete yields a low initial sorptivity and absorbed water quantity, which may have beneficial improvement on the freeze/thaw resistance and de-icing salt scaling resistance of concrete.

Freeze thaw and deicer salt scaling resistance of concrete prepared with alkali aluminosilicate cement

Concrete materials were prepared with a cement based primarily on the alkali aluminosilicate chemistry. Two aspects of concrete performance were emphasized and compared against those of ordinary Portland cement (OPC) concrete: freeze-thaw durability, and deicer salt scaling resistance. Test results indicated that the concrete prepared with the alkali aluminosilicate cement (AAC) produced excellent freeze-thaw durability; its dicer salt scaling resistance, however, was lower than that provided by the OPC concrete. Efforts were made to improve the deicer salt scaling resistance of the AAC concrete through refinement of the AAC composition. The use of an air-entraining agent was found to enhance the deicer salt scaling resistance of the AAC concrete. Modification of the AAC chemistry with polyethylene glycol, tartaric acid, or a combination of sodium benzoate and triisopropanolamine was found to also improve the AAC concrete resistance to deicer salt scaling with minimal effect on compressive strength.

Criteria for Freeze-Thaw Resistant Concrete Mixtures

Abstract Concrete, especially for improved durability, is typically specified with prescriptive provisions. More recently there has been increasing interest in evolving towards performance-based specifications, both within state highway agencies and industry (FHWA, 2014, “Guide to Developing Performance-Related Specifications, FHWA-RD-98-155, FHWA-RD-98-156, FHWA-RD-98-171, Vol. III, Appendix C,” http://www.fhwa.dot.gov/publications/research/infrastructure/pavements/pccp/pavespec/, last accessed July 28, 2014; ACI Committee 329, Report on Performance-Based Requirements for Concrete, American Concrete Institute, Farmington Hills, 2010; The P2P Initiative, 2014, “National Ready Mixed Concrete Association, Silver Spring,” http://www.nrmca.org/p2p/, last accessed July 28, 2014). One of the challenges in successfully implementing performance-based specifications is the existence and use of reliable test methods and specification criteria that can measure the potential durability of concrete mixtures and provide the expected service life. A state pooled fund research project (TPF-5 (179), 2014, “Evaluation of Test Methods for Permeability (Transport) and Development of Performance Guidelines for Durability,” http://www.pooledfund.org/Details/Study/406, last accessed July 28, 2014) was developed with an objective to propose performance criteria for concrete that will be resistant to penetration of chlorides, cycles of freezing and thawing, and sulfate attack. This paper summarized results pertaining to freeze-thaw resistance. Concrete freeze-thaw (F-T) performance was evaluated by ASTM C666/C666M-15 (AASHTO T161-08 (Standard Method of Test for Resistance of Concrete to Rapid Freezing and Thawing, Standard Specifications for Transportation Materials and Methods of Sampling and Testing, Part 2A: Tests, AASHTO, Washington DC, 2013)) and deicer salt scaling resistance was evaluated by ASTM C672/C672M-12. It was examined whether F-T performance of concrete correlated with results of rapid index tests for fluid transport characteristics of concrete. These tests included the rapid chloride permeability, absorption, and initial and secondary sorptivity. The impact of degree of saturation on the F-T resistance of concrete was also explored. Criteria for F-T resistant concrete mixtures depending on type of exposure were suggested.

Evaluation of Modifications to the ASTM C672 Deicer Salt Scaling Test for Concrete Containing Slag Cement

Abstract The standard ASTM C672/C672M-12 deicer salt scaling resistance test has been found to be overly aggressive to concretes containing slag cement or fly ash. It was compared to the recently adopted CSA A23.2-22A test method, based on the Quebec BNQ test, as well as several modifications, including use of an accelerated curing regime developed by Virginia (VADOT). Sixteen concrete mixtures were studied using high-alkali cement, low-alkali cement, grade 100 slag and grade 120 slag with slag contents of 0, 20, 35, and 50 %. Vinsol resin air-entraining admixture (AEA) was compared to a synthetic AEA. Modifications to the test method used in this study resulted in improved deicer scaling performance of concretes containing slag and many of these modifications have been incorporated into the CSA A23.2-22A test method. While it was found that increasing the level of slag replacement resulted in increased scaling, it was found that for slag mixtures, the synthetic AEA provided an improved air void spacing factor, higher hardened air content, and improved scaling resistance compared to Vinsol resin AEA.

De-Icing Salt Scaling Damage Kinetics of Fibre Reinforced Concretes Made with High Bond Crimped Steel Fibres

Durability of steel fibre reinforced concrete (SFRC) specimens is tested and evaluated. Concrete is mixed with moderately sulphate resistant CEM I 42.5 cement and does not contain airentraining agent. The aim of the research is to study how the dosage of high bond crimped steel fibre influences the durability damage kinetics of SFRC; freeze-thaw resistance, de-icing salt scaling resistance and resistance to water penetration are studied, completed with basic mechanical performance tests (compressive strength, modulus of elasticity, flexural tensile strength, splitting tensile strength, flexural toughness, fracture toughness, apparent porosity and vacuum water absorption). Results reveal the importance of the increased volume of the interface transition zone (ITZ) around the steel fibres in the first freeze-thaw cycles and the importance of the internal restrain activated by the steel fibres during later freeze-thaw cycles.

Effect of entrained air voids on salt scaling resistance of concrete containing a new composite cement

Salt scaling is a major damage problem for concrete pavements in cold environments. Salt scaling is a type of superficial damage caused by freezing and thawing a saline solution on the surface of concrete. Effects of a new composite Portland cement and air void on deicer scaling resistance of concrete were investigated in this paper. Another objective is to investigate effects of compressive strength, tensile strength, abrasion resistance and water penetration on the freeze-thaw deicer salt scaling. Specimens were tested for freeze-thaw deicer salt scaling resistance in accordance with ASTM C672 test method. Surface strengths of concrete play an important role in salt scaling resistance. There is no appropriate relationship between compressive strength and salt scaling resistance, when concrete mixtures are made with various cementitious materials. Results reveal that the mixture containing composite Portland cement with entrained air bubbles has the best performance in salt scaling test.

Influence of air entraining agents on deicing salt scaling resistance and transport properties of high-volume fly ash concrete

Based on laboratory tests, the deicing salt scaling resistance of high-volume fly ash (HVFA) concrete is usually reported as less than satisfactory. Therefore, we developed a HVFA composition with an air entraining agent (AEA) that should meet the European salt scaling criterion (⩽1 kg/m2). This paper presents a full characterization of its air void system from the moment of casting until the freeze/thaw test on cast surfaces, and evaluates the influence of air entrainment on its transport properties. The minimum air content of 6–7% was achieved with 7.0 ml AEA/kg binder (versus 2.0 ml AEA/kg binder for traditional concrete). However, with very fine fly ash (45 μm fineness: 13.2% retained), it was more difficult to maintain an adequate air void system and control the salt scaling resistance at later age (91 days). With coarser fly ash (45 μm fineness: 26.6% retained), salt scaling after 28 severe freeze/thaw cycles equaled only 0.5 kg/m2. Nevertheless, AEA use increased the water sorption under vacuum and the apparent gas permeability.

Water-binder Ratio Influence on De-icing Salt Scaling of Fly Ash Concretes

The influence of water-binder ratio on de-icing salt scaling of hardened concretes with siliceous fly ash addition is analysed in the paper. The analysis made on the basis of 56 cycles scaling Borås test of air-entrained concretes. The levels of water-binder ratio (w/b): 0.45 and 0.38, the partial replacement of cement with fly ash (0, 20, 35, 50% mass of cement), and kind of siliceous fly ash in three categories of loss on ignition A, B and C were variable in concrete mixes. The results show that apart from air-entraining, which was the sufficient condition to ensure freeze-thaw resistance, also the lowest value of water-binder ratio is necessarily to ensure de-icing salt scaling resistance of fly ash concretes. Loss on ignition of fly ash has significant influence on resistance to scaling only in air-entrained concretes with 0.45 water-binder ratio.

Deicing salt scaling resistance of concrete incorporating fly ash and (or) silica fume: laboratory and field sidewalk test data

Sidewalk sections were cast in fall 2002 with three concrete mixtures that consisted of a control concrete, a concrete mixture incorporating 25% fly ash, and a concrete mixture made with a ternary blended cement (fly ash and silica fume). The curing practices consisted of using curing compound and wet burlap. For each of the sidewalk sections, laboratory specimens were cast on site using the concrete from the same batch. Large slabs (1.2 m × 0.9 m) were also cast from which specimens could be cored and tested in the laboratory for compressive strength and deicing salt scaling resistance following the ASTM and the BNQ test procedures. The results were compared to the performance of the sidewalk sections after six winters of outdoor exposure. A similar study was completed on sidewalk sections cast in spring 2002; the objective of the present study being to confirm the results of the previous investigation, and to determine the effect of the time of casting on the scaling resistance of the concrete i.e., performance of sidewalks cast in spring versus that of sidewalks cast in fall. The field evaluation showed that all the concretes cast in fall scaled relatively more than those placed in spring. Both laboratory results and field evaluations have shown that the use of a curing compound increases the scaling resistance of all the concretes investigated. The results also confirmed the adequateness of the BNQ procedure to better evaluate the deicing salt scaling resistance of concrete made with supplementary cementing materials; however, monitoring the sidewalk sections for a longer period of time is still required to confirm the above observations.

Determination of the optimum conditions for de-icing salt scaling resistance of concrete by visual examination and surface scaling

One of the main objectives of this work is to determine the most important parameter that affects the scaling resistance of concrete. Another objective is to investigate combined effects of finishing treatment and air-entrainment on the freeze–thaw scaling of horizontal concrete surfaces subjected to de-icing salt exposure. The parameters studied in this work were; water–cement ratio, cement content, curing condition, the air-entraining admixture, and second finishing treatment. The total number of freeze–thaw cycles was 50. In the experiments, both visual examination according to ASTM C 672 and scaling test methods were considered. The parameters studied were optimized using Taguchi Optimisation Method. It has been shown that the use of de-icing salt on concrete surface causes gradual deterioration from the surface into the inner section. There is a significant positive effect of air-entrainment on the freeze–thaw scaling at horizontal concrete surfaces. It can be concluded that the second finishing treatment has a positive effect on first cycles but loses its effect on the proceeding cycles.

Capillary suction model for characterizing salt scaling resistance of concrete containing GGBFS

Abstract This paper presents a rational method to characterize the freeze–thaw salt scaling performance of concrete based on capillary suction forces. The testing program included evaluating the concrete’s chemical chloride binding capacity, degree of hydration, total porosity, compressive strength, sorptivity and de-icer salt scaling resistance conducted at both, 28 days and 2 years. Mixtures consisted of paste and concrete containing 0–60% GGBFS as cement replacement, and a water-to-binder ratio of 0.31 or 0.38. The proposed capillary suction model was adapted to include the concrete’s chloride binding capacity, pore characteristics, and age. Results from the capillary suction model are found to correlate with experimentally measured ionic sorption coefficients. Results revealed that the capillary suction depth decreases with increasing percentages of GGBFS due to blocking of capillary pores as a result of the chemical interaction between the saline solution and the binder material. A freeze–thaw salt scaling resistance factor (F/T SSRF) is proposed which accounts for the concrete’s degree of hydration, sorptivity and tensile strength and is shown to correlate with the concrete’s cumulative mass loss tested in accordance with MTO LS-412. Accordingly, the salt scaling performance of concrete containing GGBFS is influenced by the combined effect of the concrete’s pore size distribution of the exposed surface, chloride binding capacity, degree of hydration, and tensile strength.

Deicing salt scaling resistance of concrete incorporating supplementary cementing materials: laboratory and field test data

In this study, sidewalk sections were made in the field using seven concrete mixtures, applying a finishing and curing practice that is commonly used in Montréal, Canada. For each of the sidewalk sections, large slabs (1.2 m × 1.2 m) were cast from which specimens were cored and tested in the laboratory for determining their basic mechanical properties and deicing salt scaling resistance following ASTM C672 test procedures. Also, during the casting of the sidewalk, companion specimens were cast on site, using concrete from the same batch, and were subjected to the same tests as the “cored” specimens. The resistance to deicing salt scaling of these “laboratory specimens” was evaluated according to ASTM C672 and to BNQ NQ 2621–900 (2002 standard of the province of Quebec, Canada) test procedures. The results were compared with the performance of the sidewalk sections after four winters of outdoor exposure. The visual evaluation of the sidewalks after four winters has confirmed the severity of the ASTM C672 procedure and the adequateness of the BNQ procedure to better evaluate the deicing salt scaling resistance of concrete made with supplementary cementing materials (SCMs). The field evaluation should, however, continue for a longer period of time to increase the confidence in the BNQ test or to allow for changes as needed.

De-icing salt scaling resistance of mechanically loaded engineered cementitious composites

This paper reports the durability performance of non-air-entrained Engineered Cementitious Composites (ECC) with different fly ash content when subjected to mechanical loading and freezing and thawing cycles in the presence of de-icing salt. ECC is a newly developed high performance fiber reinforced cementitious composite with substantial benefit in both high ductility in excess of 3% under uniaxial tensile loading and improved durability due to intrinsically tight crack width. After 50 freezing and thawing cycles in the presence of de-icing salt, the surface condition visual rating and total mass of the scaling residue of ECC, even those with high volume fly ash content, remain within acceptable limits according to the ASTM C 672. This level of durability holds true even for specimens pre-loaded to cracking at high deformation level. Non-air-entrained mortar specimens with and without fly ash were also used as reference specimens. As expected, these mortar prisms under identical testing conditions deteriorated severely. Pre-loaded and virgin (no pre-loading) ECC coupon specimens were also exposed to freezing and thawing cycles in the presence of de-icing salts for 25 and 50 cycles to determine their residual tensile behavior. The reloaded specimens showed negligible loss of ductility, but retained the multiple micro-cracking behavior and tensile strain capacity of more than 3%. It is also discovered that multiple micro-cracks due to mechanical loading will heal sufficiently under freezing and thawing cycles in the presence of salt solutions to restore nearly the original stiffness. These results confirmed that ECC, both virgin and micro-cracked, remain durable despite exposure to freezing and thawing cycles in the presence of de-icing salts.

Deicer Salt Scaling Resistance of Concrete Containing Manufactured Sands

Abstract Manufactured sands are produced by crushing rock deposits to produce a fine aggregate which is generally more angular and has a rougher surface texture than naturally weathered sand particles. Manufactured sands can also contain significant quantities of rock dust. As natural sand deposits become depleted near some areas of metropolitan growth, the use of manufactured sands as a replacement fine aggregate in concrete is receiving attention. Designers, specifiers, contractors, and material suppliers need to understand the effects of manufactured sand particle shape characteristics and angularity as well as fines content on concrete water demand and concrete durability, including the effects of interrelationships between manufactured sand characteristics. As part of a comprehensive research program, manufactured sand properties and their effects on fresh concrete properties, mechanical properties and concrete durability were investigated. Concrete containing commercially available manufactured sands with a wide range of particle angularities and fines contents were included in the laboratory testing program on deicer salt scaling. Angularity of particles and quantity of fines were found to contribute to salt scaling.